The field of invention relates generally to semiconductor device processing. More particularly, the present invention is directed to a method of planarizing the surface of a semiconductor substrate.
Micro-fabrication involves the fabrication of very small structures, e.g., having features on the order of micro-meters or smaller. One area in which micro-fabrication has had a sizeable impact is in the processing of integrated circuits. As the semiconductor processing industry continues to strive for larger production yields while increasing the circuits per unit area formed on a substrate, micro-fabrication becomes increasingly important. Micro-fabrication provides greater process control while allowing increased reduction of the minimum feature dimension of the structures formed. Other areas of development in which micro-fabrication has been employed include biotechnology, optical technology, mechanical systems and the like.
As the minimum feature size of structures formed on substrates is reduced, there is an increasing desire to form a substrate having a substantially planar surface. A method of planarizing a substrate is disclosed in U.S. Pat. No. 5,736,424 to Prybyla et al. Prybyla et al. describes a method of planarizing a nonplanar surface by coating the nonplanar surface with a material having a viscosity of less than 1000 centipose, contacting the material with an object having a flat surface in such a manner that the material is planarized to a desired degree, curing the material while in contact with the object, and then separating the object.
Another method of planarizing a substrate is disclosed in U.S. Pat. No. 6,218,316 to Marsh. Marsh describes a method of planarizing a substrate having a planarization material disposed thereon. Specifically, a substantially flat surface is brought into contact with the planarization material on the substrate; the planarization material is then exposed to radiation at a first wavelength of light to cure the planarization material and exposed to radiation at a second wavelength of light to facilitate separation of the substantially flat surface from the planarization material.
It is desired, therefore, to provide an improved method of planarizing a substrate.